The present invention is generally concerned with an improved laryngoscope for the visualisation of the larynx and the vocal cords. The improved laryngoscope of the present invention is particularly, although not exclusively, suitable for use by physicians, especially by anaesthetists in procedures requiring the tracheal intubation of patients. The improved laryngoscope of the present invention may also be used in veterinary practice.
The tracheal intubation of patients generally requires the precise positioning of the head of a supine patient and use of a laryngoscope in the mouth to manipulate the pharyngeal structures and prevent the tongue and epiglottis from obscuring the laryngeal opening. A laryngoscope may carry a light bulb or fibre optic light system so as to illuminate the glottis and facilitate visualisation of the laryngeal opening for passage of an endotracheal tube through the larynx into the trachea.
One problem with the use of prior art laryngoscopes, whether it be just for visualisation, or for tracheal intubation, arises from the fact that there is an inherent tendency in use, often accentuated by inexperience, poor technique or tiredness, for the operator to position, or maintain the position of the blade by applying a levering action to the operating handle. This levering action uses the patient""s upper teeth as a fulcrum around which the blade of the laryngoscope is turned. Unfortunately this can exert undue pressure and is the cause of dental injury often accompanying procedures involving laryngoscopy. The levering action is more likely where long procedures or other conditions complicate the use of the laryngoscope, for example, where the patient has atypical anatomy of the mouth or the patient""s jaw experiences muscular spasm.
This tendency to lever a laryngoscopic blade is well known to those skilled in the art and the results of such incorrect use are found to be lessened by providing the laryngoscopic blade with a widened or resilient back so as to spread the load that may be acting on the teeth.
Although the use of different laryngoscope blade designs, for example the McCoy levering blade, may in fact reduce the possibility of incorrect usage none entirely removes the risk. Consequently there is still a need to provide an improved laryngoscope for preventing or reducing damage to a patient""s teeth during laryngoscopy.
The present invention addresses the problem of incorrect use of a laryngoscope and potential damage to teeth during laryngoscopy by providing an improved laryngoscope which at least reduces the risk that levering forces will be applied by the operator in use.
The present invention therefore provides a laryngoscope comprising a blade having a surface for engaging the tongue of a patient by means of an operating handle manipulated by the operator in which the said operating handle lies out of the plane normal to the tongue-contacting surface of the said blade.
Preferably the angle that the longitudinal axis of the said operating handle makes to the plane normal to the tongue-contacting surface of the said blade is adjustable.
In a preferred embodiment of the invention the said angle is 90xc2x0, that is, the longitudinal axis of the said operating handle is perpendicular to the plane normal to the tongue-contacting surface of the said blade.
In another embodiment of the invention the said blade and the said operating handle may be integrally formed.
In yet another embodiment of the invention the distance between the root of the said blade and the connecting end of the said operating handle is adjustable.
In still another embodiment the angle that the longitudinal axis of the operating handle makes to the longitudinal axis of the root of the blade is adjustable.